苗期调亏灌溉对夏玉米植株抗倒伏性状的影响

针对黄淮海平原夏玉米生产中干旱和倒伏问题,选用浚单20和伟科702两个高产品种为材料,采取盆栽调亏灌溉的方法,在苗期设置4个干旱胁迫水平,并在拔节期复水至正常水平,研究苗期不同程度的水分亏缺对玉米植株抗倒伏性状及产量的影响。结果表明,轻度干旱胁迫能降低玉米乳熟期穗位系数及长粗比,增加茎粗系数、地上第3节茎秆的穿刺强度及茎秆拉力。此外,轻度干旱胁迫的气生根及总根条数、根干重和根冠比较对照也有明显提高。灌浆期单株总叶面积及产量随干旱胁迫呈先增高后降低的趋势,其中,千粒重的变化是造成产量差异的关键。苗期轻度干旱胁迫结合拔节期复水,可以改善玉米农艺性状,增强茎秆抗倒伏能力,提高玉米子粒产量。

Effects on Lodging Resistance of Summer Maize by Regulated Deficit Irrigation at Seedling Stage

In the face of drought stress and lodging in summer maize production in Huanghuaihai Plain, by the methods of regulated deficit irrigation(RDI), two maize varieties(Xundan 20 and Weike702) and four gradients under drought stress at seedling stage were designed, and re-watering at the jointing stage, being aimed to study the effects on lodging resistance and yield by regulated deficit irrigation at seedling stage. The results showed that the mild drought stress could reduce the ear height coefficient, length to diameter ratio, increase the stem diameter coefficient, the rind penetration strength and strength of the third stem aboveground. In addition, brace roots, total number of roots, dry weight of roots and the root shoot ratio could increase during the mild drought stress. The leaf areas and yield increased firstly and then decrease with the aggravation of the drought stress, and the grain weight was the key issue which affected the yield variation. In summary, using the methods of mild drought dress at seedling stage and re-watering at jointing stage could improve agronomic traits of the summer maize, enhance the resistance to lodging and increase yield level.